//
// file_handler.cpp
// ~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2013 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#include "file_handler.hpp"
#include <fstream>
#include <sstream>
#include <string>
#include <boost/lexical_cast.hpp>
#include "mime_types.hpp"
#include "reply.hpp"
#include "request.hpp"

namespace http {
  namespace server {

    file_handler::file_handler(const std::string& doc_root)
      : doc_root_(doc_root)
    {
    }

    void file_handler::operator()(const request& req, reply& rep)
    {
      // Decode url to path.
      std::string request_path;
      if (!url_decode(req.uri, request_path))
      {
        rep = reply::stock_reply(reply::bad_request);
        return;
      }

      // Request path must be absolute and not contain "..".
      if (request_path.empty() || request_path[0] != '/'
          || request_path.find("..") != std::string::npos)
      {
        rep = reply::stock_reply(reply::bad_request);
        return;
      }

      // If path ends in slash (i.e. is a directory) then add "index.html".
      if (request_path[request_path.size() - 1] == '/')
      {
        request_path += "index.html";
      }

      // Determine the file extension.
      std::size_t last_slash_pos = request_path.find_last_of("/");
      std::size_t last_dot_pos = request_path.find_last_of(".");
      std::string extension;
      if (last_dot_pos != std::string::npos && last_dot_pos > last_slash_pos)
      {
        extension = request_path.substr(last_dot_pos + 1);
      }

      // Open the file to send back.
      std::string full_path = doc_root_ + request_path;
      std::ifstream is(full_path.c_str(), std::ios::in | std::ios::binary);
      if (!is)
      {
        rep = reply::stock_reply(reply::not_found);
        return;
      }

      // Fill out the reply to be sent to the client.
      rep.status = reply::ok;
      char buf[512];
      while (is.read(buf, sizeof(buf)).gcount() > 0)
        rep.content.append(buf, is.gcount());
      rep.headers.resize(2);
      rep.headers[0].name = "Content-Length";
      rep.headers[0].value = boost::lexical_cast<std::string>(rep.content.size());
      rep.headers[1].name = "Content-Type";
      rep.headers[1].value = mime_types::extension_to_type(extension);
    }

    bool file_handler::url_decode(const std::string& in, std::string& out)
    {
      out.clear();
      out.reserve(in.size());
      for (std::size_t i = 0; i < in.size(); ++i)
      {
        if (in[i] == '%')
        {
          if (i + 3 <= in.size())
          {
            int value = 0;
            std::istringstream is(in.substr(i + 1, 2));
            if (is >> std::hex >> value)
            {
              out += static_cast<char>(value);
              i += 2;
            }
            else
            {
              return false;
            }
          }
          else
          {
            return false;
          }
        }
        else if (in[i] == '+')
        {
          out += ' ';
        }
        else
        {
          out += in[i];
        }
      }
      return true;
    }

  } // namespace server
} // namespace http
